Tried to unlock - now all apps stopped working

Hello everyone - today I tried to unlock my Galaxy S5 SM-G900W8 using Android 5.1.1 using a tutorial i found on the internet and everything appeared to go as planned. However upon rebooting even though my home screen looks normal when I swipe the screen to use the phone I am faced with every application giving me a message like:

And so on and if you keep pressing ok it seems that all apps have stopped and the screen is just black. I could really use some advice please, I have already tried to restart into recovery mode and delete my cache but it did not work.

You're running a Canadian version of the S5. Who is your carrier? And what kind of "unlock" were you trying? Unlock it so you can use a different carrier? Also - any reason why you wouldn't have this on 6.0.1 by now? All the Canadian carriers have pushed this version out. Please give us more details so we can try to help you out.